A fluorescent immunochromatographic strip based on CsPbBr3/CsPb2Br5@SiO2 facile encapsulation in pure water for the detection of human chorionic gonadotropin (HCG) antigen

Fluorescent immunochromatographic test (FICT) strips have received extensive attention due to their virtue of simple operation, low cost, and a point-of-care (POC) assay. In recent years, people are constantly seeking new labels to improve the sensitivity of immunosensors. Perovskite nanocrystals (PNCs) possess strong fluorescence and a narrow emission peak, making them an excellent choice as a new fluorescent signal label. Herein, we have developed a simple, fast, and environmentally friendly method to synthesize CsPbBr3/CsPb2Br5@SiO2 with the good water stability and high biocompatibility. These CsPbBr3/CsPb2Br5@SiO2 have been applied to construct FICT strips. To achieve the quantitative determination of human chorionic gonadotropin (HCG), a lab-made FICT strips detection system was established. The FICT strips had a good linear relationship to HCG in the range of 5-500 ng/mL, and the detection limit was 2.09 ng/mL. In addition, the recovery results of HCG detection in human urine samples also proved the feasibility of this FICT strips. CsPbBr3/CsPb2Br5@SiO2 can also be modified with different biomarkers for functionalization, which exhibits a promising application in the development of sensing platform of FICT strips.